{"id":13420604,"url":"https://github.com/pnggroup/libpng","last_synced_at":"2026-01-15T22:20:31.528Z","repository":{"id":2769368,"uuid":"3768025","full_name":"pnggroup/libpng","owner":"pnggroup","description":"LIBPNG: Portable Network Graphics support, official libpng repository","archived":false,"fork":false,"pushed_at":"2026-01-12T22:49:52.000Z","size":44152,"stargazers_count":1531,"open_issues_count":164,"forks_count":751,"subscribers_count":52,"default_branch":"libpng18","last_synced_at":"2026-01-13T03:35:53.683Z","etag":null,"topics":[],"latest_commit_sha":null,"homepage":"http://libpng.sf.net","language":"C","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":"other","status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/pnggroup.png","metadata":{"files":{"readme":"README.md","changelog":"CHANGES","contributing":null,"funding":null,"license":"LICENSE.md","code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null,"governance":null,"roadmap":null,"authors":"AUTHORS.md","dei":null,"publiccode":null,"codemeta":null,"zenodo":null,"notice":null,"maintainers":null,"copyright":null,"agents":null,"dco":null,"cla":null}},"created_at":"2012-03-19T20:01:17.000Z","updated_at":"2026-01-11T18:53:49.000Z","dependencies_parsed_at":"2025-12-25T23:02:07.257Z","dependency_job_id":null,"html_url":"https://github.com/pnggroup/libpng","commit_stats":{"total_commits":4250,"total_committers":91,"mean_commits":46.7032967032967,"dds":0.2129411764705882,"last_synced_commit":"f1848a3b560ddcad065242268433af475948461e"},"previous_names":["glennrp/libpng"],"tags_count":1628,"template":false,"template_full_name":null,"purl":"pkg:github/pnggroup/libpng","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/pnggroup%2Flibpng","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/pnggroup%2Flibpng/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/pnggroup%2Flibpng/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/pnggroup%2Flibpng/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/pnggroup","download_url":"https://codeload.github.com/pnggroup/libpng/tar.gz/refs/heads/libpng18","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/pnggroup%2Flibpng/sbom","scorecard":null,"host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":286080680,"owners_count":28447922,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2026-01-15T05:05:00.929Z","status":"ssl_error","status_checked_at":"2026-01-15T05:04:58.515Z","response_time":62,"last_error":"SSL_connect returned=1 errno=0 peeraddr=140.82.121.5:443 state=error: unexpected eof while reading","robots_txt_status":"success","robots_txt_updated_at":"2025-07-24T06:49:26.215Z","robots_txt_url":"https://github.com/robots.txt","online":false,"can_crawl_api":true,"host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":[],"created_at":"2024-07-30T22:01:37.197Z","updated_at":"2026-01-15T22:20:31.522Z","avatar_url":"https://github.com/pnggroup.png","language":"C","funding_links":[],"categories":["TODO scan for Android support in followings","Image Processing","C"],"sub_categories":[],"readme":"README for libpng version 1.8.0.git\n===================================\n\nSee the note about version numbers near the top of `png.h`.\nSee `INSTALL` for instructions on how to install libpng.\n\nLibpng comes in several distribution formats.  Get `libpng-*.tar.gz`\nor `libpng-*.tar.xz` if you want UNIX-style line endings in the text\nfiles, or `lpng*.7z` or `lpng*.zip` if you want DOS-style line endings.\n\nFor a detailed description on using libpng, read `libpng-manual.txt`.\nFor examples of libpng in a program, see `example.c` and `pngtest.c`.\nFor usage information and restrictions (what little they are) on libpng,\nsee `png.h`.  For a description on using zlib (the compression library\nused by libpng) and zlib's restrictions, see `zlib.h`.\n\nYou should use zlib 1.0.4 or later to run this, but it _may_ work with\nversions as old as zlib 0.95.  Even so, there are bugs in older zlib\nversions which can cause the output of invalid compression streams for\nsome images.\n\nYou should also note that zlib is a compression library that is useful\nfor more things than just PNG files.  You can use zlib as a drop-in\nreplacement for `fread()` and `fwrite()`, if you are so inclined.\n\nzlib should be available at the same place that libpng is, or at\nhttps://zlib.net .\n\nYou may also want a copy of the PNG specification.  It is available\nas an RFC, a W3C Recommendation, and an ISO/IEC Standard.  You can find\nthese at http://www.libpng.org/pub/png/pngdocs.html .\n\nThis code is currently being archived at https://libpng.sourceforge.io\nin the download area, and at http://libpng.download/src .\n\nThis release, based in a large way on Glenn's, Guy's and Andreas'\nearlier work, was created and will be supported by myself and the PNG\ndevelopment group.\n\nSend comments, corrections and commendations to `png-mng-implement`\nat `lists.sourceforge.net`.  (Subscription is required; visit\nhttps://lists.sourceforge.net/lists/listinfo/png-mng-implement\nto subscribe.)\n\nSend general questions about the PNG specification to `png-mng-misc`\nat `lists.sourceforge.net`.  (Subscription is required; visit\nhttps://lists.sourceforge.net/lists/listinfo/png-mng-misc\nto subscribe.)\n\nHistorical notes\n----------------\n\nThe libpng library has been in extensive use and testing since mid-1995.\nVersion 0.89, published a year later, was the first official release.\nBy late 1997, it had finally gotten to the stage where there hadn't\nbeen significant changes to the API in some time, and people have a bad\nfeeling about libraries with versions below 1.0.  Version 1.0.0 was\nreleased in March 1998.\n\nNote that some of the changes to the `png_info` structure render this\nversion of the library binary incompatible with libpng-0.89 or\nearlier versions if you are using a shared library.  The type of the\n`filler` parameter for `png_set_filler()` has changed from `png_byte`\nto `png_uint_32`, which will affect shared-library applications that\nuse this function.\n\nTo avoid problems with changes to the internals of the `info_struct`,\nnew APIs have been made available in 0.95 to avoid direct application\naccess to `info_ptr`.  These functions are the `png_set_\u003cchunk\u003e` and\n`png_get_\u003cchunk\u003e` functions.  These functions should be used when\naccessing/storing the `info_struct` data, rather than manipulating it\ndirectly, to avoid such problems in the future.\n\nIt is important to note that the APIs did not make current programs\nthat access the info struct directly incompatible with the new\nlibrary, through libpng-1.2.x.  In libpng-1.4.x, which was meant to\nbe a transitional release, members of the `png_struct` and the\n`info_struct` can still be accessed, but the compiler will issue a\nwarning about deprecated usage.  Since libpng-1.5.0, direct access\nto these structs is not allowed, and the definitions of the structs\nreside in private `pngstruct.h` and `pnginfo.h` header files that are\nnot accessible to applications.  It is strongly suggested that new\nprograms use the new APIs (as shown in `example.c` and `pngtest.c`),\nand older programs be converted to the new format, to facilitate\nupgrades in the future.\n\nThe additions since 0.89 include the ability to read from a PNG stream\nwhich has had some (or all) of the signature bytes read by the calling\napplication.  This also allows the reading of embedded PNG streams that\ndo not have the PNG file signature.  As well, it is now possible to set\nthe library action on the detection of chunk CRC errors.  It is possible\nto set different actions based on whether the CRC error occurred in a\ncritical or an ancillary chunk.\n\nThe additions since 0.90 include the ability to compile libpng as a\nWindows DLL, and new APIs for accessing data in the `info_struct`.\nExperimental functions included the ability to set weighting and cost\nfactors for row filter selection, direct reads of integers from buffers\non big-endian processors that support misaligned data access, faster\nmethods of doing alpha composition, and more accurate 16-to-8 bit color\nconversion.  Some of these experimental functions, such as the weighted\nfilter heuristics, have since been removed.\n\nFiles included in this distribution\n-----------------------------------\n\n    ANNOUNCE.md   =\u003e  Announcement of this version, with recent changes\n    AUTHORS.md    =\u003e  List of contributing authors\n    CHANGES       =\u003e  Description of changes between libpng versions\n    LICENSE.md    =\u003e  License to use and redistribute libpng\n    README.md     =\u003e  This file\n    TODO.md       =\u003e  Things not implemented in the current library\n    TRADEMARK.md  =\u003e  Trademark information\n    example.c     =\u003e  Example code for using libpng functions\n    png.c         =\u003e  Basic interface functions common to library\n    png.h         =\u003e  Library function and interface declarations (public)\n    pngpriv.h     =\u003e  Library function and interface declarations (private)\n    pngconf.h     =\u003e  System specific library configuration (public)\n    pngstruct.h   =\u003e  png_struct declaration (private)\n    pnginfo.h     =\u003e  png_info struct declaration (private)\n    pngdebug.h    =\u003e  debugging macros (private)\n    pngerror.c    =\u003e  Error/warning message I/O functions\n    pngget.c      =\u003e  Functions for retrieving info from struct\n    pngmem.c      =\u003e  Memory handling functions\n    pngbar.png    =\u003e  PNG logo, 88x31\n    pngnow.png    =\u003e  PNG logo, 98x31\n    pngpread.c    =\u003e  Progressive reading functions\n    pngread.c     =\u003e  Read data/helper high-level functions\n    pngrio.c      =\u003e  Lowest-level data read I/O functions\n    pngrtran.c    =\u003e  Read data transformation functions\n    pngrutil.c    =\u003e  Read data utility functions\n    pngset.c      =\u003e  Functions for storing data into the info_struct\n    pngtest.c     =\u003e  Library test program\n    pngtest.png   =\u003e  Library test sample image\n    pngtrans.c    =\u003e  Common data transformation functions\n    pngwio.c      =\u003e  Lowest-level write I/O functions\n    pngwrite.c    =\u003e  High-level write functions\n    pngwtran.c    =\u003e  Write data transformations\n    pngwutil.c    =\u003e  Write utility functions\n    arm/          =\u003e  Optimized code for ARM Neon\n    intel/        =\u003e  Optimized code for INTEL SSE2\n    loongarch/    =\u003e  Optimized code for LoongArch LSX\n    mips/         =\u003e  Optimized code for MIPS MSA and MIPS MMI\n    powerpc/      =\u003e  Optimized code for PowerPC VSX\n    riscv/        =\u003e  Optimized code for the RISC-V platform\n    ci/           =\u003e  Scripts for continuous integration\n    contrib/      =\u003e  External contributions\n        arm-neon/     =\u003e  Optimized code for the ARM-NEON platform\n        mips-msa/     =\u003e  Optimized code for the MIPS-MSA platform\n        powerpc-vsx/  =\u003e  Optimized code for the POWERPC-VSX platform\n        examples/     =\u003e  Examples of libpng usage\n        gregbook/     =\u003e  Source code for PNG reading and writing, from\n                          \"PNG: The Definitive Guide\" by Greg Roelofs,\n                          O'Reilly, 1999\n        libtests/     =\u003e  Test programs\n        pngexif/      =\u003e  Program to inspect the EXIF information in PNG files\n        pngminim/     =\u003e  Minimal decoder, encoder, and progressive decoder\n                          programs demonstrating the use of pngusr.dfa\n        pngminus/     =\u003e  Simple pnm2png and png2pnm programs\n        pngsuite/     =\u003e  Test images\n        riscv-rvv/    =\u003e  Optimized code for the RISC-V Vector platform\n        testpngs/     =\u003e  Test images\n        tools/        =\u003e  Various tools\n        visupng/      =\u003e  VisualPng, a Windows viewer for PNG images\n    manuals/      =\u003e  Manuals\n        libpng-install.txt  =\u003e  Instructions to install libpng\n        libpng-manual.txt   =\u003e  Description of libpng and its functions\n        libpng.3      =\u003e  Manual page for libpng (includes libpng-manual.txt)\n        png.5         =\u003e  Manual page for the PNG format\n    projects/     =\u003e  Project files and workspaces for various IDEs\n        owatcom/      =\u003e  OpenWatcom project\n        visualc71/    =\u003e  Microsoft Visual C++ 7.1 workspace\n        vstudio/      =\u003e  Microsoft Visual Studio workspace\n    scripts/      =\u003e  Scripts and makefiles for building libpng\n                      (see scripts/README.txt for the complete list)\n    tests/        =\u003e  Test scripts\n\nGood luck, and happy coding!\n\n * Cosmin Truta (current maintainer, since 2018)\n * Glenn Randers-Pehrson (former maintainer, 1998-2018)\n * Andreas Eric Dilger (former maintainer, 1996-1997)\n * Guy Eric Schalnat (original author and former maintainer, 1995-1996)\n   (formerly of Group 42, Inc.)\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fpnggroup%2Flibpng","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fpnggroup%2Flibpng","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fpnggroup%2Flibpng/lists"}